Roche’s US arm Genentech has confirmed a total of 5 deaths in adult patients who were dosed with its to-be hemophilia blockbuster emicizumab (Hemlibra), a BITE antibody that mimics the effect of Factor VIII which lack patients with hemophilia A.

Roche’s US arm Genentech, which received FDA market approval for the bispecific antibody co-developed with Chugai last December (EU: February 2018, Japan March 2018), reported yesterday that it had few pieces of information that they can share on the exact circumstances of the deaths, which occurred from 2016 to 2018. Investigators and treating physicians, however, suggested that the deaths have all been deemed unrelated to Hemlibra.

According to a spokesman, one of the patients who died after dosing of Hemlibra participated in an extended access programme, one had been enroled in a clinical Phase II trial, and three received the medicine following a compassionate use request.

However, deaths by bleeding episodes are common with current hemophilia treatments in the contested US$11bn hemophilia market in which Hemlibra is expected to achieve peak sales of US$4bn, as the missing blood-clotting protein factor VIII in patients with the rare genetic disease is currently treated with replacement therapy via frequent infusions of recombinant factor VIII products. Besides these, huge prices have been paid by Sanofi for licensing novel treatment approaches in the competitive market currently dominated by Shire (FEIBA) and Novo Nordisk (NovoSeven) but also Biogen (Eloctate), Bayer, Pfizer, and CSL Behring.

Genentech had previously reported three cases of thrombotic microangiopathy and two cases of thromboembolic events from late-stage trials with Hemlibra. Roche’s Japanese arm Chugai, however, announced today that a Tokyo court had ruled Shire’s claim regarding Hemlibra should be dismissed. According to Reuters, Shire’s Baxalta unit had also sued over alleged patent violations in the US as it seeks to protect haemophilia products put under pressure by Roche’s new drug

Roche’s US Genentech unit seems to have learned its pharmacovigilance lessons from a case dating back to 2012, in which data on 80,000 adverse events of approved Roche meds werenot properly reported.